The overall goals of the CAVR Immunology Core are to provide a centralized resource for analysis of SIV- and SHIV-specific humoral immune responses in serum and mucosal specimens and to standardize the performance of flow cytometric assays that will be carried out by individual laboratories. A comprehensive range of well-standardized and quantitative assays of humoral immunity will be offerered, including a panel of complementary assays for the determination of neutralizing antibody responses and a newly developed assay that provides sensitive and reproducible determination of ADCC activity. To ensure consistent generation of polychromatic flow cytometry data and assays of cell-mediated immunity, the Immunology Core will coordinate the generation of consensus standard operating protocols (SOPs) for immunophenotyping and cytokine flow cytometry (CFC) assays, and supervise the implementation and validation of each SOP at each location. Specific Aims include: 1. To provide a centralized resource for the analysis of SIV/SHlV-specific antibodies in sera using ELISA and SIV/SHIV neutralization assays; 2. To provide a centralized resource for analysis of SIV and SHIV-specific antibody responses in vaginal and rectal secretions; and 3. To ensure standardization of immunophenotyping and ICS assays conducted by different sites through the development of consensus protocols, implementation of proficiency testing, and comparative evaluation of flow cytometric data analysis. These activities will provide a comprehensive and robust assessment of host immune responses elicited by these vaccine approaches and will help define responses that are able to interrupt mucosal transmission of lentiviruses.